1. Field of the Invention
The present invention relates to a system for controlling a data transfer and a method of controlling a data transfer, and more particularly controlling a data transfer so as to receive valid data in progression when the input data includes the valid data and invalid data.
The present application claims priority under 35 U.S.C. §1 19 to Japanese Patent Application No. 2001-78509, filed Mar. 19, 2001, which is herein incorporated by reference in its entirely for all purposes.
2. Description of the Related Art
In a conventional system for controlling a data transfer, a receiving apparatus can receive a valid data only in response to an enable signal which has a predetermined bit byte width of a valid data bus, when the conventional receiving apparatus receives the data from a data bus which has an optional bit byte width.
Another conventional system for controlling a data transfer removes the invalid data from an input data, and then only the valid data is stored as an output data. Such a conventional system for controlling a data transfer is hereinafter described.
FIG. 13 is an explanation diagram describing conventional data processing and data storing. At first, the invalid data which is unnecessary for an operation is removed from input data 20, 22, 24, 26, 28 and 30 by software processing. It is noted that in FIG. 2, “X” is indicative of invalid data and “−” is indicative of no data. Then, only the valid data which is necessary for the operation is stored as output data 40, 42, 44, 46, 48 and 50. Therefore, a continuity of the valid data which is necessary for the operation can be maintained.
However, conventional system for controlling a date transfer can not maintain the continuity of valid data, if the receiving apparatus does not use the enable signal and also does not perform data processing using software. There is thus a need to provide a control system and method which can maintain the continuity of valid data to thereby output the valid data only, without using enable signals which indicate the predetermined bit byte width of a valid data bus, and without using data processing using software, when a receiving apparatus receives data through a data bus which has an optional bit byte width.